Heart disease is a major health risk in the United States and elsewhere. One well-known treatment approach utilizes an implantable medical device, like a cardiac pacing device (i.e., a pacemaker) or a defibrillator, to manage a patient's heart rate or correct cardiac arrhythmias. An arrhythmia is generally defined as an abnormal cardiac rhythm.
A pacemaker delivers a relatively mild, periodic electrical impulse to epicardial or endocardial tissue as necessary to maintain normal sinus rhythm. In comparison to a pacemaker, an implanted defibrillator applies a much stronger electrical stimulus to the heart to “shock” it into a normal rhythm. The electrical charges for both implanted pacemakers and defibrillators are applied through electrically conductive leads that emanate from the medical device and terminate at an appropriate location on the tissue.
Suture sleeves are used to secure the implanted lead at the implant site. Suture sleeves are generally configured as tubular members, the cavity or lumen of which is adapted to sheathe the electrically conductive lead body of an implantable medical device. A suture sleeve also includes circumferential grooves adapted to receive a suture. The circumferential grooves facilitate wrapping the suture sleeve with a suture to secure the sleeve to the body of a lead and to a patient's body tissue, usually the fascia tissue of the heart. Suture sleeves are typically formed of soft, implantable elastomer material, such as silicone.
Suture sleeves come in various forms. Some come from the implantable medical device manufacturer or other distributor with the lead already sheathed by the suture sleeve, thereby eliminating the need to thread or feed the lead through the sleeve during surgery. Other suture sleeves are separate from the lead, and the lead must be fed through the sleeve. Still other suture sleeves include a slit along the longitudinal axis of the sleeve to allow the sleeve to sheathe a lead body by passing the lead through the slit into the cavity or lumen of the suture sleeve.
Once the lead body is sheathed within the suture sleeve and properly positioned at the implant site, the suture sleeve is slid down the lead body to a point near the implant site and wrapped with a suture in the circumferential groove. The suture is pulled tight and tied to longitudinally secure the suture sleeve to the lead. The suture sleeve is then sutured to body tissue. Securing a suture sleeve in this manner is important to provide permanent hemostasis and lead stabilization at the implant site.
However, because suture sleeves must be moved along the longitudinal axis of the lead body during the implantation procedure and are constructed of soft, pliable material, problems may occur. For example, because the inner lumen of a typical suture sleeve is generally cylindrical, friction due to contact between the inside of the suture sleeve and the body of the lead may cause the sleeve to stick to the lead and make it difficult or impossible to slide the sleeve along the longitudinal axis of the lead body. On other occasions, if the clinician pulls the suture too tight when securing the sleeve to the lead, the suture can cut through the soft material of the suture sleeve and the insulation surrounding the lead, thereby damaging the lead. When this happens, the lead must be replaced. Unfortunately, damage to the lead is often not detected until after the surgery is complete, thereby requiring additional surgery to correct the problem and ultimately increasing the total cost of the implantation procedure.
Thus, for these and other reasons, there is a need for a strengthened or reinforced suture sleeve that reduces the risk of a suture cutting through the sleeve and damaging the lead.